A cap with or without a clip is provided on a writing implement to enclose the writing tip for its protection. When using the writing implement, an infant or child can place it in his or her mouth and accidentally swallow it. In that event, the cap without the clip can not define any air passage in the throat, resulting in the risk of asphyxiation.
The inventors are aware of (A) Japanese patent public disclosure Heisei 1-157898, (B) Japanese utility modele public disclosure Heisei 1-169384, (C) Japanese utility modele public disclosure Heisei 1-169385, (D) Japanese utility modele public disclosure Heisei 1-169386, (E) UK patent application BG 2174374 A, (F) Japanese utility modele public disclosure Heisei 2-58981, (G) Offenlegungsschrift DE 3817248, (H) Offenlegungsschrift DE 3821195 which proposed to reduce or eliminate the abave-mentioned disadvantages.
Application (A) discloses a cap having air passages formed in a portion protruding radially outwardly of the outer cylindrical surface thereof. This arrangement of the cap has an disadvantage that the cap has a larger external dimension and much more material is required for molding of the cap, resulting in a high cost of production. In addition, the air passages are in an elongated form which may encounter a difficulty in molding.
Application (B) discloses a cap comprising separate outer and inner caps connected to each other at the top of the outer cap. This arrangement leads to a high cost of production due to the fact that there is a need of separately molding the outer and inner caps.
Furthermore, upon fitting the cap over the writing implement, the writing tip is liable to enter an annular space defined between the outer and inner caps, leading to damage thereto.
Application (C) discloses a cap having longitudinal grooves formed in an inner cap on its outer surface. With this arrangement, a thicker wall of the cap is required, resulting in a high cost of production.
Application (D) has substantially the same disadvantage as Application (B).
UK Application (E) discloses a cap having slots formed therein adjacent the open end. This arrangement has the disadvantage that the writing tip is liable to enter the slots in fitting the cap thereover.
Each of Applications (F) and (G) discloses a cap having air passages defined between an outer and an inner cap and opening adjacent the open end thereof. With this arrangement, the writing tip has the risk of entering the air passages.
Application (H) has a disadvantage that a structure of the mold to be used for molding of the cap becomes complicated.